Study on Soil Heavy Metal Contamination and Risk Estimation in Sixian

Abstract

At present, heavy metal contamination of soils is a extensive attention on account of the develop rapidly of urbanization and industrialization. In this paper, topsoil samples were gathered and the contents of heavy metals for example: Cd, Cr, Cu, Zn, As and Pb were determined in Sixian City. The contamination degree of heavy metals and potential ecological risk were estimated using uniparted factor contamination index, Nemero integrated contamination method, geo-accumulation index, and potential ecological risk method. The results showed: except As, mean concentrations of Pb, Zn, Cu, Cr and Cd were greater than soil background values in Sixian City. The coefficient of variation of Zn, Pb, Cu and As are greater than 30%, suggesting that they were more probably affected by human disturbance in the soil of Sixian City. The Pc values ranged between 1.46 and 26.83, displaying almost whole survey region is varying degrees contamination because of heavy metals. The Igeo showed that the average values implied the follow contamination order: Pb > Cd > Cu > Zn > As > Cr. The most serious element is Pb. The Ei values of Cu, Zn, As and Cr were observed in the ranges 5.66 to 21.15, 0.74 to 3.13 and 3.99 to 39.42, 1.54 to 3.57, respectively. The RI values were less than 150 with 85% light potential ecological risk and 15% moderate risk.